PARASITIC COPEPODS — WILSON 549 



On the front of the head can be seen a pair of rudimentary first 

 antennae apparently 1-segniented and a pair of second antennae in 

 the form of stout claws evidently used as accessory attachment 

 organs, but there are no traces of mouth parts or SAvimming legs. 

 Total length from toe to heel of the body horseshoe, 13 mm. Diam- 

 eter of the sides of the horseshoe, 4 mm. Length of ovisacs, 8.4 mm. 

 Distance of lateral horns from tip to tip, 6.5 mm. 



Remarks. — Tha form and body proportions as given above are 

 sufficient to distinguish this unique copepod from all others. 



Family EUDACTYLINIDAE 



Genus KR0YERINA Wilson, 1932 



KR0YERINA ELONGATA Wilson 

 Pl-\te 32, Figures 180-185 



Kr0yerina elongata Wilson, 1932, p. 459, pi. 31, figs. 1-p. 



This species was established upon female specimens only from 

 the gills of great blue sharks {^''Galeus glaucus''') at Marthas Vine- 

 yard, Mass. The present material consists of 50-odd specimens of 

 both sexes, taken from the gills of a tiger shark {Galcocerdo tigri- 

 nits), caught at Woods Hole. These are the first males obtained. 

 One has been designated the allotype, U.S.N.M. No. 79613. 



Male. — Body elongate and narrow, head fused with the first seg- 

 ment and covered with a triangular carapace one-fifth wider than 

 long. Segments 2 to 4 the same length but diminishing in width ; the 

 fused fifth and genital segments one-third longer than the three pre- 

 ceding segments combined and the same width as the fourth segment. 

 Abdomen 3-segmented, the segments diminishing in length and width 

 distally, but the anal segment is still three-fifths as long as the basal 

 segment. The latter has an enlarged ring or collar around its proxi- 

 mal end which looks like an extra segment, but it is not separated. 

 Caudal rami narrow and rodlike, as long as the anal segment, parallel 

 with each other, each tipped with three setae. 



First antennae 7-segmented, every segment bearing setae ; the second 

 antennae stout and chelate. Second maxillae shorter and stouter than 

 in the female; maxillipeds with a curved terminal claw. The four 

 pairs of swimming legs are biramose, the rami 3-segmented as in the 

 female. Total length, 5-6 mm. Fifth and genital segments, 1.30 mm. 

 long. 



Remarhs. — This male closely resembles that of K. na^'<uta (Wilson, 

 1932, p. 457), with these differences : It is more than twice as large, the 

 fused fifth and genital segment is relatively longer, the first abdominal 



